Search

Tens of thousands of species are at risk of extinction globally. In many ecosystems, species declines are associated with deforestation. However, forest degradation also can profoundly affect biodiversity. I present a detailed case study of species declines associated with forest degradation in southeastern Australia's montane ash (Eucalyptus spp.) forests. The case study is based on ~40 years of long-term monitoring focused on declines (and potential extinction trajectories) of arboreal marsupials and birds, with a particular emphasis on key drivers, especially logging, wildfire, habitat loss, climate change, and interactions among these drivers. I discuss policy failures contributing to species declines, including ongoing logging of high-conservation-value forests, poor regulation of forest management, and inadequate design of reserves. I conclude with general lessons for better conservation and forest management efforts aimed at reducing forest degradation and loss of ecosystem integrity. I contend that ongoing logging in already highly degraded montane ash forests is inconsistent with the Australian government's commitment at the Glasgow COP26 meeting in 2021 on halting forest degradation. Similarly, the Australian Government has committed to preventing further extinctions in Australia, yet its current support for ongoing logging in montane ash forests through federal–state legislation will likely promote extinctions for some species. The inherent conflicts and contradictions between conservation and logging policies need to be addressed. [ABSTRACT FROM AUTHOR]

Large quantities of dead wood can be generated by disturbances such as wildfires. Dead trees created by disturbances play many critical ecological roles in forest ecosystems globally. The ability of deadwood to serve its ecological roles is contingent, in part, on the length of time trees remain standing following disturbance. Here, we briefly outline the results of a 10‐year study that aimed to quantify the rate of collapse of trees killed in a major wildfire in the wet ash forests of mainland south‐eastern Australia. We also quantified the factors associated with dead tree collapse. Our analyses revealed that 23% of 417 measured trees collapsed between 2011 and 2021. The most parsimonious model of the factors influencing tree collapse revealed a strong effect of diameter; smaller diameter trees were more likely to collapse over the 10 years of our study than larger diameter trees. In addition, trees in small and large patches were more likely to collapse than trees in contiguous forest (where there had been no logging in the surrounding area). If current rates of tree fall are maintained, then many of trees initially measured will have collapsed by 2030. Such losses of dead trees will have major negative effects on key values of ash‐type forests such as biodiversity conservation. [ABSTRACT FROM AUTHOR]

Aim: The distribution and abundance of forest biodiversity can be shaped by multiple drivers, including disturbances like wildfires. We quantified the influence of wildfire severity and bird life history attributes on temporal patterns of bird site occupancy. Location: Wet eucalypt forests of Victoria, Australia. Methods: We employed a Before, After, Control, Impact experimental design, gathering occupancy data on birds 5 years before, and for 10 years after, a wildfire in 2009. We quantified post‐fire decline and then recovery on sites subject to high‐severity fire, comparing these temporal patterns with those for birds at sites that were unburnt or burnt at moderate severity. We also tested the influence of life history attributes on bird responses to wildfire. Data were analysed using joint species distribution modelling, accounting for imperfect detection. Results: We found a two‐way interaction between fire severity and time period for overall bird site occupancy. The largest change between time periods was on sites burnt at high severity where bird occupancy declined immediately after fire followed by a strong recovery. Occupancy patterns remained largely unchanged on unburnt sites. For many individual species, interactions between fire severity and time period were similar to overall species occupancy. On sites subject to high‐severity fire, most species recovered to pre‐fire levels within 6 years. We found no evidence of a three‐way interaction between fire severity, time period, and life history attributes, with all trait groups of birds examined largely recovered to pre‐fire site occupancy levels 10 years post‐fire. Main conclusions: The Victorian 2009 wildfires were severe, but their impacts on common bird species were relatively short‐lived, with immediate post‐fire declines mostly reversed within ~10 years. Rapid post‐fire stand regeneration appears a likely driver of these responses and may account for the relatively limited influence of life history attributes on bird species recovery. However, diet influenced bird species occupancy after fire, with nectivores recovering slower than insectivores on sites subject to high severity fire. Our findings may be relevant to other forests types globally where there can be rapid post‐fire vegetation growth and stand regeneration. [ABSTRACT FROM AUTHOR]

Millions of trees are expected to be planted in forested and non‐forested ecosystems during the United Nations Decade of Restoration. Trees and soil organisms are known to interact, and are both crucial for maintaining multiple ecosystem functions. However, little is known about how the bidirectional relationships among above‐ and below‐ground diversity and ecosystem functions differ across forested and non‐forested ecosystems.We collected data from 126 sites from humid to arid areas in eastern Australia to explore bidirectional relationships among above‐ground (richness of trees and other plants) and below‐ground (richness of bacteria, fungi, invertebrate, protist) diversity and multiple ecosystem functions (multifunctionality, litter and labile carbon storage, nutrient pools, decomposition, groundstorey plant biomass production, soil stability) in forested (tree cover >10%) and non‐forested (tree cover ≤10%, open woodlands, shrublands) systems.We found that the relative importance of above‐ and below‐ground diversity differed among forested and non‐forested systems. Ecosystem functions, such as litter and labile carbon storage and soil stability, were associated mainly with tree richness in forested systems. By comparison, ecosystem functions of non‐forests were related to the richness of soil organisms. Such bidirectional biodiversity–ecosystem function relationships varied with the target function, and the relationships among ecosystem functions and the relative abundance of species varied with tree and soil taxa. The richness of other plants (i.e. all plants excluding trees) and soil organisms was positively coupled in forests only, but there were no linkages among above‐ and below‐ground diversity and ecosystem functions in non‐forests for groundstorey plant biomass production. Furthermore, increases in aridity and soil pH further weakened the biodiversity–ecosystem function relationships in forested and non‐forested systems, by suppressing above‐ground diversity and bacterial richness, respectively.Synthesis. Our study provides strong empirical evidence that the bidirectional relationships among above‐ and below‐ground diversity and ecosystem functions are highly variable across ecosystem and function types. Moreover, our study demonstrates that soil biodiversity is relatively more important than tree diversity in supporting ecosystem functions in non‐forested systems. This suggests that conservation of soil biodiversity is critical for maintaining the functioning of open woodland and shrubland systems. [ABSTRACT FROM AUTHOR]